I think it's perfectly normal to have those kinds of thoughts and fears (about the dance instructor). Just even allowing yourself to ENTERTAIN the though of being single again always seemed really strange to me when I was going thru my sitch with my wife 7 years ago. At times it seemed exciting, even liberating; other times, it scared the hell out of me. It was all just so . . . so weird.
Just keep your wits about you and don't go starting any new Rs right now, until you guys either reconcile or wrap things up. It wouldn't be fair to anyone involved.